Scleritis - Types, Causes, Diagnosis, and Treatment

What Is Sclera?

The sclera is a connective tissue that forms the eyeball's outer fibrous layer. It is the tough white layer of the eye. The sclera is needed for maintaining the shape of the eye. In simpler terms, the sclera is nothing but the visible white portion of the eye surrounding the pupil.

What Is Scleritis?

Any inflammation that occurs in the sclera is called scleritis. Scleritis, if it involves the episclera (the outer membrane that covers the sclera) and uvea, can bring about problems in vision. The amount of pain associated with scleritis is high; however, it may differ in some cases. An underlying disease is present in more than half of the individuals affected with scleritis.

How Is Scleritis Different From Episcleritis?

Episcleritis is the inflammation involving the outer membrane that covers the eyes' sclera, whereas scleritis is the inflammation of the sclera. Episcleritis is a more familiar, less painful, and less severe condition.

What Are the Types of Scleritis?

Scleritis can be either unilateral or bilateral; that is, it can be present in one eye or can involve both eyes.

According to Watson and Hayreh, scleritis is classified into the following types:

Based on location, it is,

• Anterior scleritis - involves the anterior or front portion of the sclera.

• Posterior scleritis - involves the rear or back portion of the sclera.

Anterior scleritis is divided into subtypes, which include the following:

• Diffuse anterior scleritis.

• Nodular anterior scleritis.

• Necrotizing anterior scleritis.

Necrotizing anterior scleritis without inflammation is also called scleromalacia perforans.

Posterior scleritis is divided into the below subtypes:

• Diffuse posterior scleritis.

• Nodular posterior scleritis.

What Is the Cause of Scleritis?

Scleritis is most commonly associated with an underlying chronic systemic condition. It can be an essential manifestation of autoimmune disorders, connective tissue disorders, and generalized vascular disorders that can have organ damaging and life-threatening effects. When an underlying systemic disease is present, scleritis usually affects both the eyes.

The systemic diseases that are associated with the presence of scleritis include the following:

• Systemic lupus erythematosus.

• Reactive arthritis.

• Ankylosing spondylitis.

• Polychondritis.

• Mixed connective tissue disease.

• Arthritis.

• Psoriatic arthritis.

• Gouty arthritis.

• Scleroderma.

• Sjogren's syndrome.

• Polymyositis.

• Polyarteritis nodosa.

• Inflammatory bowel disease.

• Giant cell arteritis.

• Granulomatous polyangiitis.

In some cases, scleritis may also have infectious causes. Bacteria, mycobacterium, pseudomonas, parasites, fungi, or viruses can also cause scleritis. In addition, exposure to chemicals or trauma can also bring about scleritis. However, the exact cause of scleritis cannot be determined in a few.

How Is Scleritis Manifested?

The symptoms are almost the same in nearly all types of scleritis. Except that in posterior scleritis, there is no severe pain and exhibits only the following symptoms:

• Double vision.

• Irritation.

• Deep-seated headaches.

The following are the manifestations of scleritis:

• Severe eye pain with no or minimal response to pain-relieving medications.

• Pain with eye movements.

• Radiating pain that affects the affected side of the face.

• Blurry vision

• Photosensitivity.

• Production of increased tears.

• Redness in the white portion or sclera of the eye.

• Reduced vision.

Why Does Scleritis Not Cause Pain in Some Patients?

Some individuals do not exhibit pain with scleritis due to the following reasons:

• Individuals with scleromalacia perforans, which is an uncommon complication of rheumatoid arthritis.

• Individuals with mild forms of scleritis.

• Individuals already on immunosuppressive medications that had reduced the disease even before the symptoms were manifested.

What Increases the Risk of Developing Scleritis?

Although scleritis does not have a specific geographic distribution, gender predisposition is seen. Women are much more likely to be affected with scleritis than men.

In addition to this, the following are the risk factors for scleritis:

• Sjogren's syndrome (an immune disorder associated with dryness of eyes and oral cavity).

• Rheumatoid arthritis (an autoimmune disorder characterized by joint inflammation).

• Lupus (skin inflammatory immune disorder).

• Wegener's granulomatosis (a disorder characterized by blood vessel inflammation).

• Inflammatory bowel disease (a digestive disorder characterized by bowel inflammation).

• Infections of the eye.

• Trauma to the eyes.

How Is Diagnosis for Scleritis Made?

1. Medical History:

Since the onset of scleritis is a gradual process, severe eye pain can be present for quite some days. Tenderness and redness might involve a small localized or a more generalized eye area.

2. Signs and Symptoms:

• Pain with movement of eyes, night pain associated with disturbance in sleep, and radiating pain to the face, scalp, and jaw are the significant symptoms that help diagnose scleritis.

• Signs of scleritis include a characteristic violet-bluish hue along with dilatation and edema involving the sclera of the eye.

• The non-ocular signs can best identify the presence of systemic conditions.

  • Wegener's granulomatosis presents hemoptysis (blood vomiting), sinusitis, and epistaxis (bleeding from the nose).

  • Presence of photosensitivity, pericarditis (inflammation of the membrane covering the heart), seizures, pleuritis (inflammation of the pleural membrane surrounding the lungs), malar rash (presence of reddish or purplish rashes on the cheeks), etc., indicate systemic lupus erythematosus.

  • Anemia, pericarditis, and the development of skin nodules indicate rheumatoid arthritis.

  • Loss of weight, myalgia (muscle aches), nephropathy (reduced kidney function), purpura (purple spots in skin due to leakage of blood vessels), and hypertension (high blood pressure) indicates polyarteritis nodosa.

3. Physical Examination:

On examination with natural light, the slight color difference between scleritis and episcleritis can help diagnose. Slit-lamp biomicroscopy shows a criss-cross pattern and adherence in scleral blood vessels. The scleral and episcleral blood vessels can be differentiated by moving with the help of a cotton-tipped applicator. When moved, the episcleral vessels move, and the scleral vessels do not move.

In addition to this, the following tests also aid in the diagnosis:

1. Complete Blood Count:

It is done to check for the presence of any infection or immune dysfunction.

2. Microscopic Examination:

Scleral tissue is removed and examined under a microscope to look for changes in some cases. This is done to rule out neoplastic or infectious causes.

3. B-Scan Ultrasonography:

Thickening of the sclera and choroid, presence of scleral nodules, collection of fluid in the Tenon's capsule, detachment of the retina, etc., are some characteristic ultrasonographic features that can be seen in scleritis.

4. Orbital magnetic resonance imaging (MRI) can also help posterior scleritis detection.

What Is the Management for Scleritis?

Treatment for scleritis can either be medical or surgical. Surgical treatment is recommended when there is an increased chance for surgical perforation or rupture. Treatment for scleritis is aimed at reducing ocular damage by decreasing inflammation.

A. Medical Treatment:

1. NSAIDs - In mild to moderate cases of scleritis, intake of oral non-steroidal anti-inflammatory drugs is the first-line drug of choice for scleritis.

2. Selective cyclo-oxygenase inhibitors or non-selective cyclo-oxygenase inhibitors like Indomethacin, Ibuprofen, or Flurbiprofen may be used in the treatment.

3. Corticosteroids - Topical corticosteroids are prescribed when patients fail to respond to NSAIDs. Prednisolone is initially started with a dosage of 1 mg/kg/day, which is then tapered according to the patient's condition. If the disease is severe, then pulsed intravenous administration of 0.5 to 1 g of Methylprednisolone is given.

4. Immunosuppressant Drugs - These are prescribed when there is an underlying autoimmune condition, and the corticosteroids fail to bring adequate results. Depending on the systemic disease, immunosuppressive drugs like Cyclophosphamide, Methotrexate, Cyclosporine, and Mycophenolate may be recommended.

5. In necrotizing scleritis, which is a dangerous condition, immunosuppressive drugs are used along with glucocorticoids to manage scleritis.

6. Antibiotics - Scleritis caused by bacterial infections is treated with antibiotics, and antifungal medications help treat scleritis caused by Sjogren's syndrome.

B. Surgical Treatment:

Surgical correction is not so commonly required in scleritis. In cases where scleral thinning occurs, scleral graft placement may be needed. Before the surgical correction, bandage contact lenses or corneal glue are used to treat the small corneal perforations. Donor sclera, periosteum, or fascia lata are obtained to help reinforce the sclera.

What Is the Prognosis of Scleritis?

Mild and moderate cases of scleritis are not usually associated with loss of vision. Only severe cases of scleritis exhibit vision loss. Also, necrotizing scleritis has a high chance of developing vision loss and death.

Conclusion:

Scleritis usually takes about a few months to even years to develop. Therefore, identifying the initial symptoms and reaching out to an ophthalmologist can help avoid serious complications. Also, when you have been diagnosed with scleritis, a diagnosis for any underlying systemic condition is needed. Once you have been diagnosed with scleritis, it is essential to have a regular follow-up with your ophthalmologist even when your symptoms are improving.